1. Field of the Invention
The present invention relates to a liquid transporting apparatus which transports a liquid, and a piezoelectric actuator.
2. Description of the Related Art
In an ink-jet head described in Japanese Patent Application Laid-open No. 2006-327031, a vibration plate made of a metallic material such as stainless steel is arranged to cover a plurality of pressure chambers, and a piezoelectric layer is formed on an upper surface of the vibration plate, and individual electrodes corresponding to the plurality of pressure chambers are formed on an upper surface of the piezoelectric layer. Moreover, by applying a voltage between the vibration plate as a common electrode and one of the individual electrodes, an electric field is generated at a portion, of the piezoelectric layer, sandwiched between the common electrode and the individual electrode in a thickness direction of the piezoelectric layer, and portions of the vibration plate and the piezoelectric layer which face the pressure chamber are deformed to form a projection toward the pressure chamber. Accordingly, a volume of the pressure chamber is decreased, and a pressure of the ink in the pressure chamber increases and the ink is jetted from a nozzle communicating with the pressure chamber.
Here, at the time of manufacturing the ink-jet head described in Japanese Patent Application Laid-open No. 2006-327031, in a case in which the vibration plate and the piezoelectric layer are joined by a thermosetting adhesive, the vibration plate and the piezoelectric layer are heated. However, in a case in which the vibration plate is formed of a material such as stainless steel having a coefficient of linear expansion greater than a coefficient of linear expansion of a piezoelectric material which forms the piezoelectric layer, when the temperature is returned to a room temperature after heating, there is a compression distortion in a planar direction of the piezoelectric layer due to a difference in the coefficient of linear expansion of the vibration plate and the piezoelectric layer. When such compression distortion occurs in the piezoelectric layer, piezoelectric characteristics are declined, and as described above, an amount of deformation of the vibration plate and the piezoelectric layer becomes small when the voltage is applied between the individual electrode and the common electrode, and an amount of jetting of ink from the nozzle decreases.